Western military action in Syria would be a "satanic intervention against a satanic regime", a leading Syrian opposition figure has warned.

Speaking to the Huffington Post UK, Haytham al-Manna, the Paris-based spokesman of the National Coordination Committee (NCC), said: "Our position is against any [western] aggression against Syria. There is no [option of] military aggression against the regime, it will be against.. the population."

The NCC, which consists of a dozen or so secular, leftist political parties inside Syria, is not a member of the Syrian National Council (SNC), the coalition of opposition groups recognised as the legitimate representative of the Syrian people by several western governments. The latter has long supported western military intervention against Assad; the former does not.

The NCC's Manna, a veteran human-rights activist whose brother was killed by the Assad regime, said US ordnance won't "make the distinction between military and civilian targets. I saw what happened in Iraq..and all the [previous] American interventions."

Manna's brother was killed by the Assad regime but he doesn't support military intervention

Manna added: "We are against the intervention in Syria of Hizbollah [and] of foreign fighters from al Qaeda. We cannot build democracy in Syria with others."

Criticising the United States, Turkey, Israel and other regional powers, he said: "We are not in favour of a satanic intervention against a satanic regime."

Several other opposition groups have criticised the NCC for being too soft on the Syrian government, with the rebel Free Syrian Army (FSA) dismissing it as "just the other face of the same coin". But Manna insisted that the "political opposition outside Syria" is a "minority inside the country". The NCC spokesman claimed that "the majority of Syrian society is against any [foreign military] intervention".

Referring to the proposed 'Geneva II' UN-backed peace conference in Switzerland, Manna warned that "we have now the opportunity.. to push all parties, the regime and the opposition, to go to Geneva.. Up to now, [the Assad regime] accepted it had to go to Geneva.. I am not sure [Assad] will go at the end of the year."

Manna wants pressure to be put on Assad and the rebels to attend peace talks in Geneva

However, most of Syria's opposition groups, as well as a growing number of Western diplomats, believe Assad will not agree to negotiate with his opponents unless there is a credible threat of US-led military action. Manna disagrees. "If [Assad] doesn't accept [he has] to go, Russia will change its position [of support] because it is an essential part of Geneva II."

Responding to his critics who take a more hardline stance against the regime, and insist on Assad's resignation as a precondition to peace talks, Manna said that the rebels had been refusing to negotiate with the Syrian president for over two years "and we lost more than 70,000 people in Syria because of this position". The prolonging of the Syrian civil war, he explained, "is only in the interests of Assad and al Qaeda".

For Manna, there is no alternative to negotiations. "The regime and the opposition must go to Geneva II without preconditions," he told HuffPost UK. "The only precondition is applying [the principles of the] Geneva communique. And this is in the interests of the democratic opposition, not of al Qaeda [or] the Islamists." The Geneva communique, published in June 2012, called on all parties to the conflict to recommit to a "sustained cessation of armed violence" and immediately implement the then UN envoy Kofi Annan's six-point peace plan.

Manna, however, pointed out that enforcing international law "is not a decision for Congress or for the French parliament.. We don't accept any unilateral decision from any country in the world, whether it is the US or Iran or the UK."